If you thought Apple made strides in the enterprise last year, it was only the first lap of a remarkable run, according to analyst firm Forrester.

How much will you spend on Apple gear this year? Probably more than ever, especially on iPads.

A Forrester report this week predicts CIOs will pour $19 billion into Apple products in 2012—$10 billion in iPads, $9 billion in Macs. This is up from around $12 billion last year, where the split between iPads and Macs was roughly even. By 2013, CIOs will spend $16 billion in iPads and $12 billion in Macs, Forrester predicts.

All of this represents a dramatic rise in the number of Apple products in the enterprise, as corporate sales of Wintel PCs drop slightly by 3 percent this year. (Of course, Wintel PCs will maintain a lion's share of the enterprise computer market with $69 billion this year, according to Forrester.)

While Apple doesn't break out consumer and business sales in its earnings report, the company claims 92 percent of Fortune 400 companies are deploying or testing iPads. Industries shown to be aggressive iPad adopters include healthcare, financial services, airlines, and even manufacturing. Apple iPads recently began making inroads at Lifetime Products, a midmarket manufacturer and former Microsoft-only shop.

A case can be made that Apple started—or at the very least now drives—the consumerization of IT trend, as well as the offshoot "bring your own device," or BYOD programs, that has caused CIOs sleepless nights. And there doesn't seem to be a whole lot of effort and scheming coming out of Cupertino.

"The Apple assault on the corporate market has so far taken place without much formal Apple support, and probably without Apple itself understanding its full extent," writes Forrester analyst Andrew Bartels in the report Global Tech Market Outlook for 2012 and 2013. "That's because corporate adoption of Apple products has been largely clandestine."

Bartels points to three ways Apple products make their way into the enterprise:

Many iPads are coming to companies through the front door—that is, IT at Fortune 500 companies are purchasing tens of thousands of iPads for employees. Case-in-point: The CEO of KLA-Tencor, a Silicon Valley semiconductor equipment maker with $1.8 billion in annual revenues, rewarded the company's 5,400 employees around the world with iPads, reported CIO.com.

Small business owners are buying Macs and iPads for both personal and business use, says Forrester. This business segment has traditionally been an Apple adopter, whereby a small business owner buys an easy-to-use Mac and writes it off as a business expense.

Lastly, CEOs and other senior executives are largely credited with forcing IT's hand to support (and perhaps reimburse) their iPhones, iPads and MacBooks. CIO.com has reported on the trickle-down movement of Apple products to other employees, which, in some cases, has resulted in formal BYOD programs.

"Anecdotal reports suggest that this 'take an Apple to work' approach is starting to get company funding and support from the IT department," Bartels writes.